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Abstract:

A heat exchanger for a vehicle may include a heat radiating portion
provided with first, second and third connecting lines and receiving
first, second, and third operating fluids respectively and a bifurcating
portion connecting one of inflow holes formed to the heat radiating
portion for flowing one operating fluid of the first, second, and third
operating fluids with one of exhaust holes formed to the heat radiating
portion for exhausting the one operating fluid, wherein the bifurcating
portion may be mounted at an exterior of the heat radiating portion, and
wherein the bifurcating portion bypasses the one operating fluid from the
heat radiating portion according to a temperature of the one operating
fluid.

Claims:

1. A heat exchanger for a vehicle, comprising: a heat radiating portion
provided with a first connecting line and second and third connecting
lines formed alternately by stacking a plurality of plates, and receiving
first, second, and third operating fluids respectively into the first,
second, and third connecting lines, the first, second, and third
operating fluids heat-exchanging with each other during passing through
the first, second, and third connecting lines respectively and the first,
second, and third operating fluids supplying into the first, second, and
third connecting lines not being mixed with each other and being
circulated; and a bifurcating portion connecting one of inflow holes
formed to the heat radiating portion for flowing one operating fluid of
the first, second, and third operating fluids with one of exhaust holes
formed to the heat radiating portion for exhausting the one operating
fluid, wherein the bifurcating portion is mounted at an exterior of the
heat radiating portion, and wherein the bifurcating portion bypasses the
one operating fluid from the heat radiating portion according to a
temperature of the one operating fluid.

2. The heat exchanger of claim 1, wherein the inflow holes include first,
second and third inflow holes and the exhaust holes include first, second
and third exhaust holes, wherein the first operating fluid flows into the
heat radiating portion through the first inflow hole and flows out from
the heat radiating portion through the first exhaust hole, and the first
inflow hole is connected to the first exhaust hole through the first
connecting line, wherein the second operating fluid flows into the heat
radiating portion through the second inflow hole and flows out from the
heat radiating portion through the second exhaust hole, and the second
inflow hole is connected to the second exhaust hole through the second
connecting line, wherein the third operating fluid flows into the heat
radiating portion through the third inflow hole and flows out from the
heat radiating portion through the third exhaust hole, and the third
inflow hole is connected to the third exhaust hole through the third
connecting line, wherein the first, second, and third inflow holes are
formed at both sides of a surface of the heat radiating portion along a
length direction, and wherein the first, second, and third exhaust holes
are distanced from the first, second, and third inflow holes and are
formed at the both sides of the surface of the heat radiating portion
along the length direction.

3. The heat exchanger of claim 2, wherein the first inflow hole and the
first exhaust hole are formed at corner portions of the surface of the
heat radiating portion facing diagonally with each other.

4. The heat exchanger of claim 2, wherein the second inflow hole and the
second exhaust hole are formed on an oblique line at a side portion of
the surface of the heat radiating portion where the first inflow hole is
formed, and the oblique line connecting the second inflow hole and the
second exhaust hole crosses a line connecting the first inflow hole and
the first exhaust hole.

5. The heat exchanger of claim 2, wherein the third inflow hole and the
third exhaust hole are formed on an oblique line at the other side
portion of the surface of the heat radiating portion where the first
exhaust hole is formed, and the oblique line connecting the third inflow
hole and the third exhaust hole crosses a line connecting the first
inflow hole and the first exhaust hole.

6. The heat exchanger of claim 2, wherein the bifurcating portion
includes: a connecting pipe connecting the first inflow hole with the
first exhaust hole at the exterior of the heat radiating portion and
having an inflow port formed at a position close to the first inflow hole
and an exhaust port confronting the inflow port and formed at a position
close to the first exhaust hole; and a valve unit mounted at one end
portion of the connecting pipe between the first inflow hole and the
inflow port, wherein the valve unit extends or contracts according to the
temperature of the one operating fluid such that the one operating fluid
flowing in through the inflow port flows directly to the exhaust port or
flows into the heat radiating portion.

7. The heat exchanger of claim 6, wherein the valve unit includes: a
mounting cap fixedly mounted to the one end portion of the connecting
pipe; and a deformable member having one end portion connected to the
mounting cap inserted in the connecting pipe, wherein the deformable
member extends or contracts according to the temperature of the one
operating fluid.

8. The heat exchanger of claim 6, wherein the one operating fluid is a
transmission oil flowing from an automatic transmission.

9. The heat exchanger of claim 7, wherein the deformable member is made
from shape memory alloy adapted to extend or contract according to the
temperature of one operating fluid.

10. The heat exchanger of claim 7, wherein the deformable member is
formed by overlapping and contacting a plurality of ring members with
each other in a coil spring shape.

11. The heat exchanger of claim 7, wherein the deformable member
includes: a pair of fixed portions positioned at both distal sides
thereof in a length direction and adapted not to being deformed according
to the temperature; and a deformable portion disposed between the pair of
fixed portions and extending or contracting according to the temperature
of the one operating fluid.

12. The heat exchanger of claim 7, wherein the mounting cap includes: an
inserting portion having one end portion inserted in and fixed to the
deformable member; and a mounting portion having one end integrally
connected to the other end of the inserting portion, and mounted at an
interior circumference of the connecting pipe.

13. The heat exchanger of claim 12, wherein a screw is formed at an
exterior circumference of the mounting portion so as to be threaded to
the interior circumference of the connecting pipe.

14. The heat exchanger of claim 12, wherein a blocking portion for being
blocked by an end portion of the connecting pipe is integrally formed
with the other end of the mounting portion.

15. The heat exchanger of claim 12, wherein a tool hole is formed at an
interior circumference of the blocking portion.

16. The heat exchanger of claim 12, further including a sealing for
preventing the one operating fluid from leaking from the connecting pipe,
wherein the sealing is mounted between the mounting portion and the
inserting portion.

17. The heat exchanger of claim 7, further including an end cap mounted
at the other end of the deformable member.

18. The heat exchanger of claim 17, wherein the end cap is provided with
a penetration hole for coping with a pressure changing according to
flowing amount of the one operating fluid flowing in through the inflow
port and flowing the one operating fluid in the deformable member so as
to improve temperature responsiveness of the deformable member.

19. The heat exchanger of claim 2, wherein the first operating fluid is a
coolant flowing from a radiator, the second operating fluid is a
transmission oil flowing from an automatic transmission, and the third
operating fluid is an engine oil flowing from an engine.

20. The heat exchanger of claim 19, wherein the coolant circulates
through the first inflow hole, the first connecting line, and the first
exhaust hole, the transmission oil circulates through the second inflow
hole, the second connecting line, and the second exhaust hole, and the
engine oil circulates through the third inflow hole, the third connecting
line, and the third exhaust hole, and wherein the second and third
connecting lines alternately formed with the first connecting line are
separated by a rib.

21. The heat exchanger of claim 20, wherein the rib is formed at a middle
portion of the heat radiating portion in the length direction so as to
prevent the transmission oil and the engine oil flowing respectively
through the second connecting line and the third connecting line from
being mixed with each other.

22. The heat exchanger of claim 1, wherein the heat radiating portion
causes the first operating fluid to exchange heat with the second and
third operating fluids by counterflow of the first operating fluid and
the second and third operating fluids.

23. The heat exchanger of claim 1, wherein the heat radiating portion is
a heat radiating portion of plate type where a plurality of plates is
stacked.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to Korean Patent
Application No. 10-2011-0122440 filed in the Korean Intellectual Property
Office on Nov. 22, 2011, the entire contents of which is incorporated
herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a heat exchanger for a vehicle.
More particularly, the present invention relates to a heat exchanger for
a vehicle which can control temperatures of operating fluids which flows
in the heat exchanger.

[0004] 2. Description of Related Art

[0005] Generally, a heat exchanger transfers heat from high-temperature
fluid to low-temperature fluid through a heat transfer surface, and is
used in a heater, a cooler, an evaporator, and a condenser.

[0006] Such a heat exchanger reuses heat energy or controls a temperature
of an operating fluid flowing therein for demanded performance. The heat
exchanger is applied to an air conditioning system or a transmission oil
cooler of a vehicle, and is mounted at an engine compartment.

[0007] Since the heat exchanger is hard to be mounted at the engine
compartment with restricted space, studies for the heat exchanger with
smaller size, lighter weight, and higher efficiency have been developed.

[0008] A conventional heat exchanger controls the temperatures of the
operating fluids according to a condition of a vehicle and supplies the
operating fluids to an engine, a transmission, or an air conditioning
system. For this purpose, bifurcation circuits and valves are mounted on
each hydraulic line through which the operating fluids operated as
heating medium or cooling medium passes. Therefore, constituent elements
and assembling processes increase and layout is complicated.

[0009] If additional bifurcation circuits and valves are not used, heat
exchanging efficiency cannot be controlled according to flow amount of
the operating fluid. Therefore, the temperature of the operating fluid
cannot be controlled efficiently.

[0010] The information disclosed in this Background of the Invention
section is only for enhancement of understanding of the general
background of the invention and should not be taken as an acknowledgement
or any form of suggestion that this information forms the prior art
already known to a person skilled in the art.

BRIEF SUMMARY

[0011] Various aspects of the present invention are directed to providing
a heat exchanger for a vehicle having advantages of simultaneously
warming up and cooling operating fluids according to temperatures of the
operating fluids at a running state or an initial starting condition of
the vehicle when the operating fluids are heat exchanged with each other
in the heat exchanger.

[0012] Various aspects of the present invention are directed to providing
a heat exchanger for a vehicle having further advantages of improving
fuel economy and heating performance by separating a connecting line
through with operating fluids fluid into two sections, flowing and
circulating different operating fluids through the two sections, and
controlling temperatures of operating fluids according to condition of
the vehicle, and of reducing assembling processes by simplifying a
structure of the heat exchanger.

[0013] In an aspect of the present invention, a heat exchanger for a
vehicle may include a heat radiating portion provided with a first
connecting line and second and third connecting lines formed alternately
by stacking a plurality of plates, and receiving first, second, and third
operating fluids respectively into the first, second, and third
connecting lines, the first, second, and third operating fluids
heat-exchanging with each other during passing through the first, second,
and third connecting lines respectively and the first, second, and third
operating fluids supplying into the first, second, and third connecting
lines not being mixed with each other and being circulated; and a
bifurcating portion connecting one of inflow holes formed to the heat
radiating portion for flowing one operating fluid of the first, second,
and third operating fluids with one of exhaust holes formed to the heat
radiating portion for exhausting the one operating fluid, wherein the
bifurcating portion is mounted at an exterior of the heat radiating
portion, and wherein the bifurcating portion bypasses the one operating
fluid from the heat radiating portion according to a temperature of the
one operating fluid.

[0014] The inflow holes include first, second and third inflow holes and
the exhaust holes include first, second and third exhaust holes, and the
first operating fluid flows into the heat radiating portion through the
first inflow hole and flows out from the heat radiating portion through
the first exhaust hole, and the first inflow hole is connected to the
first exhaust hole through the first connecting line, wherein the second
operating fluid flows into the heat radiating portion through the second
inflow hole and flows out from the heat radiating portion through the
second exhaust hole, and the second inflow hole is connected to the
second exhaust hole through the second connecting line, wherein the third
operating fluid flows into the heat radiating portion through the third
inflow hole and flows out from the heat radiating portion through the
third exhaust hole, and the third inflow hole is connected to the third
exhaust hole through the third connecting line, wherein the first,
second, and third inflow holes are formed at both sides of a surface of
the heat radiating portion along a length direction, and wherein the
first, second, and third exhaust holes are distanced from the first,
second, and third inflow holes and are formed at the both sides of the
surface of the heat radiating portion along the length direction.

[0015] The first inflow hole and the first exhaust hole are formed at
corner portions of the surface of the heat radiating portion facing
diagonally with each other.

[0016] The second inflow hole and the second exhaust hole are formed on an
oblique line at a side portion of the surface of the heat radiating
portion where the first inflow hole is formed, and the oblique line
connecting the second inflow hole and the second exhaust hole crosses a
line connecting the first inflow hole and the first exhaust hole.

[0017] The third inflow hole and the third exhaust hole are formed on an
oblique line at the other side portion of the surface of the heat
radiating portion where the first exhaust hole is formed, and the oblique
line connecting the third inflow hole and the third exhaust hole crosses
a line connecting the first inflow hole and the first exhaust hole.

[0018] The bifurcating portion includes: a connecting pipe connecting the
first inflow hole with the first exhaust hole at the exterior of the heat
radiating portion and having an inflow port formed at a position close to
the first inflow hole and an exhaust port confronting the inflow port and
formed at a position close to the first exhaust hole; and a valve unit
mounted at one end portion of the connecting pipe between the first
inflow hole and the inflow port, wherein the valve unit extends or
contracts according to the temperature of the one operating fluid such
that the one operating fluid flowing in through the inflow port flows
directly to the exhaust port or flows into the heat radiating portion.

[0019] The valve unit includes: a mounting cap fixedly mounted to the one
end portion of the connecting pipe; and a deformable member having one
end portion connected to the mounting cap inserted in the connecting
pipe, wherein the deformable member extends or contracts according to the
temperature of the one operating fluid.

[0020] The one operating fluid is a transmission oil flowing from an
automatic transmission.

[0021] The deformable member is made from shape memory alloy adapted to
extend or contract according to the temperature of one operating fluid.

[0022] The deformable member is formed by overlapping and contacting a
plurality of ring members with each other in a coil spring shape.

[0023] The deformable member includes: a pair of fixed portions positioned
at both distal sides thereof in a length direction and adapted not to
being deformed according to the temperature; and a deformable portion
disposed between the pair of fixed portions and extending or contracting
according to the temperature of the one operating fluid.

[0024] The mounting cap includes: an inserting portion having one end
portion inserted in and fixed to the deformable member; and a mounting
portion having one end integrally connected to the other end of the
inserting portion, and mounted at an interior circumference of the
connecting pipe.

[0025] A screw is formed at an exterior circumference of the mounting
portion so as to be threaded to the interior circumference of the
connecting pipe.

[0026] A blocking portion for being blocked by an end portion of the
connecting pipe is integrally formed with the other end of the mounting
portion.

[0027] A tool hole is formed at an interior circumference of the blocking
portion.

[0028] The heat exchanger may further include a sealing for preventing the
one operating fluid from leaking from the connecting pipe, wherein the
sealing is mounted between the mounting portion and the inserting
portion.

[0029] The heat exchanger may further include an end cap mounted at the
other end of the deformable member.

[0030] The end cap is provided with a penetration hole for coping with a
pressure changing according to flowing amount of the one operating fluid
flowing in through the inflow port and flowing the one operating fluid in
the deformable member so as to improve temperature responsiveness of the
deformable member.

[0031] The first operating fluid is a coolant flowing from a radiator, the
second operating fluid is a transmission oil flowing from an automatic
transmission, and the third operating fluid is an engine oil flowing from
an engine.

[0032] The coolant circulates through the first inflow hole, the first
connecting line, and the first exhaust hole, the transmission oil
circulates through the second inflow hole, the second connecting line,
and the second exhaust hole, and the engine oil circulates through the
third inflow hole, the third connecting line, and the third exhaust hole,
and wherein the second and third connecting lines alternately formed with
the first connecting line are separated by a rib.

[0033] The rib is formed at a middle portion of the heat radiating portion
in the length direction so as to prevent the transmission oil and the
engine oil flowing respectively through the second connecting line and
the third connecting line from being mixed with each other.

[0034] The heat radiating portion causes the first operating fluid to
exchange heat with the second and third operating fluids by counterflow
of the first operating fluid and the second and third operating fluids.

[0035] The heat radiating portion is a heat radiating portion of plate
type where a plurality of plates is stacked.

[0036] The methods and apparatuses of the present invention have other
features and advantages which will be apparent from or are set forth in
more detail in the accompanying drawings, which are incorporated herein,
and the following Detailed Description, which together serve to explain
certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1 is a schematic diagram of a cooling system of an automatic
transmission to which a heat exchanger for a vehicle according to an
exemplary embodiment of the present invention is applied.

[0038]FIG. 2 is a perspective view of a heat exchanger for a vehicle
according to an exemplary embodiment of the present invention.

[0039]FIG. 3 is a cross-sectional view taken along the line A-A in FIG.
2.

[0040] FIG. 4 is a cross-sectional view taken along the line B-B in FIG.
2.

[0041]FIG. 5 is a perspective view of a valve unit used in a heat
exchanger for a vehicle according to an exemplary embodiment of the
present invention.

[0042] FIG. 6 is an exploded perspective view of a valve unit according to
an exemplary embodiment of the present invention.

[0043] FIG. 7 is a perspective view of a valve unit at an extended state
according to an exemplary embodiment of the present invention.

[0044]FIG. 8 to FIG. 10 are perspective and cross-sectional views for
describing operation of a heat exchanger for a vehicle according to an
exemplary embodiment of the present invention.

[0045] It should be understood that the appended drawings are not
necessarily to scale, presenting a somewhat simplified representation of
various features illustrative of the basic principles of the invention.
The specific design features of the present invention as disclosed
herein, including, for example, specific dimensions, orientations,
locations, and shapes will be determined in part by the particular
intended application and use environment.

[0046] In the figures, reference numbers refer to the same or equivalent
parts of the present invention throughout the several figures of the
drawing.

DETAILED DESCRIPTION

[0047] Reference will now be made in detail to various embodiments of the
present invention(s), examples of which are illustrated in the
accompanying drawings and described below. While the invention(s) will be
described in conjunction with exemplary embodiments, it will be
understood that the present description is not intended to limit the
invention(s) to those exemplary embodiments. On the contrary, the
invention(s) is/are intended to cover not only the exemplary embodiments,
but also various alternatives, modifications, equivalents and other
embodiments, which may be included within the spirit and scope of the
invention as defined by the appended claims.

[0048] An exemplary embodiment of the present invention will hereinafter
be described in detail with reference to the accompanying drawings.

[0049] Exemplary embodiments described in this specification and drawings
are just exemplary embodiments of the present invention. It is to be
understood that there can be various modifications and equivalents
included in the spirit of the present invention at the filing of this
application.

[0050] FIG. 1 is a schematic diagram of a cooling system of an automatic
transmission to which a heat exchanger for a vehicle according to an
exemplary embodiment of the present invention is applied, FIG. 2 is a
perspective view of a heat exchanger for a vehicle according to an
exemplary embodiment of the present invention, FIG. 3 is a
cross-sectional view taken along the line A-A in FIG. 2, FIG. 4 is a
cross-sectional view taken along the line B-B in FIG. 2, FIG. 5 is a
perspective view of a valve unit used in a heat exchanger for a vehicle
according to an exemplary embodiment of the present invention, and FIG. 6
is an exploded perspective view of a valve unit according to an exemplary
embodiment of the present invention.

[0051] Referring to the drawings, a heat exchanger 100 for a vehicle
according to an exemplary embodiment of the present invention applies to
a cooling system of an automatic transmission for a vehicle.

[0052] The cooling system of the automatic transmission, as shown in FIG.
1, is provided with a cooling line C.L for cooling an engine 50. A
coolant passes through the radiator 20 having a cooling fan 21 through a
water pump 10 and is cooled by the radiator 20. A heater core 30
connected to a heating system of the vehicle is mounted at the cooling
line C.L.

[0053] A heat exchanger 100 for a vehicle according to an exemplary
embodiment of the present invention warms up or cools operating fluids
according to temperatures of the operating fluids flowing in at a running
state or an initial starting condition of the vehicle when the
temperatures of the operating fluids are controlled in the heat exchanger
100 through heat exchange.

[0054] For this purpose, the heat exchanger 100 for a vehicle according to
an exemplary embodiment of the present invention is disposed between the
water pump 10 and the heater core 30, and is connected to an automatic
transmission 40 and the engine 50 through first and second oil lines O.L1
and O.L2.

[0055] That is, the operating fluids includes a coolant flowing from the
radiator 20, a transmission oil flowing from the automatic transmission
40, and an engine oil flowing from the engine 50 according to the present
exemplary embodiment. The heat exchanger 100 causes transmission oil and
the engine oil to exchange heat with the coolant such that temperatures
of the transmission oil and the engine oil are controlled.

[0056] The heat exchanger 100, as shown in FIG. 2, includes a heat
radiating portion 110 and a bifurcating portion 120, and the heat
radiating portion 110 and the bifurcating portion 120 will be described
in detail.

[0057] The heat radiating portion 110 is formed by stacking a plurality of
plates 112, and a plurality of connecting lines 114 is foamed between the
neighboring plates 112. In addition, the coolant flows through one of the
neighboring three connecting lines 114, the transmission oil flows
through another of the neighboring three connecting lines 114, and the
engine oil flows through the other of the neighboring three connecting
lines 114. At this time, the coolant exchanges heat with the transmission
oil and the engine oil.

[0058] In addition, the operating fluid supplied to the connecting line
114 is not mixed with the operating fluid supplied to other connecting
line 114s.

[0059] Herein, the heat radiating portion 110 causes the coolant to
exchange heat with the transmission oil and the engine oil by counterflow
of the coolant and the transmission and engine oils.

[0060] The heat radiating portion 110 is a heat radiating portion of plate
type (or disk type) where the plurality of plates 112 is stacked.

[0061] In addition, the bifurcating portion 120 connects one of inflow
holes 116 for flowing the operating fluids into the heat radiating
portion 110 with one of exhaust holes 118 for discharging the operating
fluids from the heat radiating portion 110, and is mounted at an exterior
of the heat radiating portion 110. The bifurcating portion 120 is
configured for the operating fluid to bypass the heat radiating portion
110 according to the temperature of the operating fluid.

[0062] The inflow holes 116 includes first, second, and third inflow holes
116a, 116b, and 116c formed at both sides of a surface of the heat
radiating portion 110 along a length direction according to the present
exemplary embodiment.

[0063] In addition, the exhaust holes 118 includes first, second, and
third exhaust holes 118a, 118b, and 118c formed at the both sides of the
surface of the heat radiating portion 110 along the length direction. The
first, second, and third exhaust holes 118a, 118b, and 118c correspond to
the first, second, and third inflow holes 116a, 116b, and 116c and are
distanced from the first, second, and third inflow holes 116a, 116b, and
116c. The first, second, and third exhaust holes 118a, 118b, and 118c are
connected respectively to the first, second, and third inflow holes 116a,
116b, and 116c through the respective connecting line 114 in the heat
radiating portion 110.

[0064] The first inflow hole 116a and the first exhaust hole 118a are
formed at corner portions of the surface of the heat radiating portion
110 diagonally.

[0065] In the present embodiment, the second inflow hole 116b and the
second exhaust hole 118b are formed on an oblique line at a side portion
of the surface of the heat radiating portion 110 where the first inflow
hole 116a is formed, and the oblique line connecting the second inflow
hole 116b and the second exhaust hole 118b crosses a line connecting the
first inflow hole 116a and the first exhaust hole 118a.

[0066] In addition, the third inflow hole 116c and the third exhaust hole
118c are formed on an oblique line at the other side portion of the
surface of the heat radiating portion 110 where the first exhaust hole
118a is formed, and the oblique line connecting the third inflow hole
116c and the third exhaust hole 118c crosses the line connecting the
first inflow hole 116a and the first exhaust hole 118a.

[0067] The bifurcating portion 120 includes a connecting pipe 122 and a
valve unit 130, and the connecting pipe 122 and the valve unit 130 will
be described in detail.

[0068] The connecting pipe 122 connects the first inflow hole 116a with
the first exhaust hole 116b at the exterior of the heat radiating portion
110, and has an inflow port 124 formed at a position close to the first
inflow hole 116a and an exhaust port 126 confronting the inflow port 124
and formed at a position close to the first exhaust hole 118a.

[0069] In addition, the valve unit 130 is mounted at an end portion of the
connecting pipe 122 corresponding to the first inflow hole 116a, and
extends or contracts according to the temperature of the operating fluid.

[0070] Accordingly, the valve unit 130 flows the operating fluid flowing
therein through the inflow port 124 directly to the exhaust port 126
without passing through the heat radiating portion 110 or passes the
operating fluid through the heat radiating portion 110 by flowing the
operating fluid into the first inflow hole 116a and then exhausting the
operating fluid from the heat radiating portion 110 through the first
exhaust hole 118a.

[0071] The coolant flowing through the inflow port 124 bypasses the heat
radiating portion 110 to the exhaust port 126 through the connecting pipe
122 or circulates through the first inflow hole 116a the heat radiating
portion 110 and the first exhaust hole 118a according to selective
operation of the valve unit 130.

[0072] In addition, the transmission oil circulates through the second
inflow hole 116b and the second exhaust hole 118b, and the engine oil
circulates through the third inflow hole 116c and the third exhaust hole
118c.

[0073] Connecting ports P are mounted respectively at the second and third
inflow holes 116b and 116c and the second and third exhaust holes 118b
and 118c, and are connected to the automatic transmission 40 and the
engine 50 through connecting hoses connected to the connecting ports P.

[0074] In addition, the inflow port 124 and the exhaust port 126 are
connected to the radiator 20 through additional connecting hoses.

[0075] In the present exemplary embodiment, the connecting line 114, as
shown in FIG. 3 and FIG. 4, includes first, second, and third connecting
lines 114a, 114b, and 114c, and will be described in detail.

[0076] The first connecting line 114a is adapted to flow the coolant
flowing into the heat radiating portion 110 through the first inflow hole
114a.

[0077] The second connecting line 114b and the third connecting line 114c
are formed alternately with the first connecting line 114a, and are
separated by a rib 140.

[0078] Herein, the rib 140 prevents the transmission oil and the engine
oil flowing respectively through the second connecting line 114b and the
third connecting line 114c from being mixed with each other. The rib 140
is formed at a middle portion of the heat radiating portion 110 in the
length direction.

[0079] That is, the rib 140 is formed at the middle portion of the
plurality of plates 112 stacked with each other in the length direction,
and separates the connecting lines formed across the first connecting
line 114a into the second and third connecting lines 114b and 114c.

[0080] Therefore, the transmission oil supplied through the second inflow
hole 116b flows through the second connecting line 114b, and the engine
oil supplied through the third inflow hole 116c flows through the third
connecting line 114c.

[0081] The valve unit 130, as shown in FIG. 5 and FIG. 6, includes a
mounting cap 132 and a deformable member 142, and the mounting cap 132
and the deformable member 142 will be described in detail.

[0082] The mounting cap 132 is fixedly mounted at an end of the connecting
pipe 122 close to the connecting port P.

[0083] The mounting cap 132 includes an inserting portion 134 having an
end portion fitted in the deformable member 142, and a mounting portion
136 integrally connected to the other end of the inserting portion 134
and mounted at an interior circumference of the connecting pipe 122.

[0084] According to the present exemplary embodiment, a screw N is formed
at an exterior circumference of the mounting portion 136 such that the
mounting portion 136 is threaded to an interior circumference of the
connecting pipe 122, and tab forming is performed at the interior
circumference of the connecting pipe 122 corresponding to the screw N.

[0085] In addition, an end of the mounting portion 136 is connected to the
inserting portion 134, and a blocking portion 138 is integrally formed at
the other end of the mounting portion 136. The blocking portion 138 is
blocked by the end portion of the connecting pipe 122 such that it is
prevented the mounting portion 136 from being inserted further in the
connecting pipe 122.

[0086] A tool hole 139 in which a tool is inserted is formed at an
interior circumference of the blocking portion 138. After the tool is
inserted in the tool hole 139, the mounting cap 132 is rotated such that
the mounting portion 136 is threaded to the connecting pipe 122.

[0087] According to the present exemplary embodiment, a sealing 141 is
mounted between the mounting portion 136 and the inserting portion 134.
The sealing 141 prevents the operating fluid flowing into the connecting
pipe 122 from being leaked from the connecting pipe 122.

[0088] That is, the sealing 141 seals a gap between the interior
circumference of the connecting pipe 122 and the exterior circumference
of the mounting portion 136 such that the operating fluid is prevented
from being leaked along the screw N of the mounting portion 136 threaded
to the connecting pipe 122.

[0089] The deformable member 142 has an end portion connected to the
mounting cap 132 inserted in the connecting pipe 122, and extends or
contracts according to the temperature of the operating fluid.

[0090] The deformable member 142 can be made from shape memory alloy that
can extend or contract according to the temperature of the operating
fluid.

[0091] The shape memory alloy (SMA) is alloy that remembers a shape at a
predetermined temperature. The shape of the shape memory alloy can be
changed at a different temperature from the predetermined temperature. If
the shape memory alloy, however, is cooled or heated to the predetermined
temperature, the shape memory alloy returns to an original shape.

[0092] The deformable member 142 made from the shape memory alloy material
includes a pair of fixed portions 144 and a deformable portion 146, and
the fixed portion 144 and the deformable portion 146 will be described in
detail.

[0093] The pair of fixed portions 144 is positioned at both end portions
of the deformable member 144 in a length direction, and a shape of the
fixed portion does not change according to the temperature.

[0094] The mounting cap 132 is connected to one fixed portion 144. The
mounting cap 132 is fixed to the deformable member 142 by fitting the
inserting portion 134 in an interior circumference of the fixed portion
144.

[0095] The deformable portion 146 is positioned between the fixed portions
144, and extends or contracts according to the temperature of the
operating fluid.

[0096] The deformable member 142 has a shape similar to that of a circular
coil spring.

[0097] According to the present exemplary embodiment, the other fixed
portion 144 is slidably inserted in the connecting pipe 122, and an end
cap 148 is mounted at the other fixed portion 144.

[0098] At a state where the deformable member 142 of the valve unit 130
extends, the end cap 148 makes the coolant flowing through the inflow
port 124 not bypass the heat radiating portion 110. That is, the coolant
is discharged to the exhaust port 126 through the first exhaust hole 118a
after passing through the first connecting line 114a.

[0099] A penetration hole 149 is formed at the end cap 148. The coolant
bypasses to the deformable member 142 through the penetration hole 149.
The penetration hole 149 copes with a pressure changing according to
flowing amount of the operating fluid flowing in through the inflow port
124 and improves temperature responsiveness of the deformable member 142.

[0100] That is, the penetration hole 149 prevents the deformable member
142 from being damaged by the pressure of the operating fluid and flows
the operating fluid into the deformable member 142 such that the
deformable member 142 responds to temperature change of the operating
fluid quickly.

[0101] If the operating fluid having a higher temperature than the
predetermined temperature flows in the valve unit 130, the deformable
portion 146 of the deformable member 142 extends, as shown in FIG. 7.

[0102] Accordingly, ring members forming the deformable portion 146 of the
deformable member 142 are distanced from each other so as to form a space
S, and the operating fluid flows in through the space S.

[0103] At this time, ring members forming the fixed portion 144 are fixed
to each other by welding, and the fixed portion 144 does not extend.

[0104] If the operating fluid having a lower temperature than the
predetermined temperature flows into the connecting pipe 122, on the
contrary, the deformable portion 146 contracts to an original shape shown
in FIG. 5 and the space S is closed.

[0105] Operation and function of the heat exchanger 100 according to an
exemplary embodiment of the present invention will be described in
detail.

[0106]FIG. 8 to FIG. 10 are perspective and cross-sectional views for
describing operation of a heat exchanger for a vehicle according to an
exemplary embodiment of the present invention.

[0107] If the temperature of the coolant flowing into the connecting pipe
122 through the inflow port 124 is lower than the predetermined
temperature, the deformable member 142 of the valve unit 130 does not
deform and maintains an original shape as shown in FIG. 8.

[0108] The coolant does not flow into the first connecting line 114a
through the first inflow hole 116a of the heat radiating portion 110, but
flows to the exhaust port 126 along the connecting pipe 122 and is
discharged through the exhaust port 126.

[0109] Accordingly, the coolant does not flow into the first connecting
line 114a of the heat radiating portion 110.

[0110] Then, the transmission oil and the engine oil flows through the
second and third inflow holes 116b and 116c and passes through the second
and third connecting lines 114b and 114c of the heat radiating portion
110. Since the coolant, however, does not flow into the first connecting
line 114a, the coolant does not exchange heat with the transmission oil
and the engine oil.

[0111] If the transmission oil and the engine oil should be warmed up
according to a condition or a mode of the vehicle such as a running
state, an idle mode, or an initial starting, the connecting pipe 122
prevents the coolant of low temperature from flowing into the first
connecting line 114a. Therefore, it is prevented that the temperatures of
the transmission oil and the engine oil are lowered through heat exchange
with the coolant.

[0112] Since the transmission oil and the engine oil are supplied to the
automatic transmission 40 and the engine 50 in a state of being warmed
up, heating performance of the vehicle may be improved.

[0113] If the temperature of the coolant, on the contrary, is higher than
the predetermined temperature, the deformable member 142 of the valve
unit 130 extends and the space S is formed between the ring members
forming the deformable portion 146 as shown in FIG. 9.

[0114] The coolant passing through the inflow port 124 flows into the
first inflow hole 116a through the space S and passes through the first
connecting line 114a of the heat radiating portion 110. After that, the
coolant is discharged to the connecting pipe 122 through the first
exhaust hole 118a.

[0115] The coolant discharged to the connecting pipe 122 flows to the
radiator 20 through the exhaust port 126 of the connecting pipe 122.

[0116] Therefore, the coolant passes through the first connecting line
114a of the heat radiating portion 110.

[0117] Therefore, the transmission oil and the engine oil supplied from
the automatic transmission 40 and the engine 50 through the second inflow
hole 116b and the third inflow hole 116c and passing through the second
and third connecting lines 114b and 114c exchange heat with the coolant
passing through the first connecting line 114a. Therefore, the
temperatures of the coolant, the transmission oil, and the engine oil are
controlled in the heat radiating portion 110.

[0118] Herein, the transmission oil and the engine oil, as shown in FIG.
10, are supplied respectively through the second inflow hole 116b and the
third inflow hole 116c, and passes respectively through the second and
third connecting lines 114b and 114c separated by the rib 140 in the heat
radiating portion 110. After that, the transmission oil and the engine
oil are supplied to the automatic transmission 40 and the engine 50
through the second exhaust hole 118b and the third exhaust hole 118c.

[0119] At this time, the coolant and the transmission oil flow to opposite
directions and exchange heat with each other.

[0120] In addition, the coolant and the engine oil flow to opposite
directions and exchange heat with each other.

[0121] Therefore, the transmission oil and the engine oil exchange heat
with the coolant more efficiently.

[0122] Therefore, the transmission oil and the engine oil, the
temperatures of which are raised by operation of a torque converter and
the engine 50, are cooled through heat exchange with the coolant in the
heat radiating portion 110 and are then supplied to the automatic
transmission 40 and the engine 50.

[0123] That is, since the heat exchanger 100 supplies the cooled
transmission oil and the cooled engine oil to the automatic transmission
40 rotating with a high speed and the engine 50, occurrence of slip in
the automatic transmission 40 and occurrence of knocking and rancidity in
the engine 50 are prevented.

[0124] In addition, the engine oil and the transmission oil are heated
through heat exchange with the coolant heated faster in the heat
radiating portion 110 when the vehicle runs with middle/high speed after
being started. After that, the transmission oil and the engine oil are
supplied to the automatic transmission 40 and the engine 50. Therefore,
friction loss in the automatic transmission 40 and the engine 50 may be
lowered and fuel economy may be improved.

[0125] The end cap 148 prevents the coolant flowing in through the inflow
port 124 at an extended state of the deformable member 142 from being
exhausted directly to the exhaust port 126 and exhausts very small amount
of the coolant through the penetration hole 149. Therefore, it is
prevented that the deformable member 142 is damaged by the pressure of
the coolant.

[0126] If the heat exchanger 100 according to an exemplary embodiment of
the present invention is applied, the operating fluids can be warmed up
and cooled simultaneously by using the temperatures of the operating
fluids at the running state or the initial starting condition of the
vehicle. Therefore, the temperatures of the operating fluids can be
controlled efficiently.

[0127] In addition, since the deformable member 142 is made from the shape
memory alloy, structure of the valve unit 130 is very simple. Since the
valve unit 130 performs conversion of the hydraulic lines of the
operating fluid according to the temperature of the operating fluid, flow
of the operating fluid can be controlled accurately. Therefore,
constituent elements can be simplified and production cost may be
curtailed. In addition, weight may be reduced.

[0128] In addition, responsiveness of the valve according to the
temperature of the operating fluid may be improved.

[0129] Since the temperatures of the operating fluids can be controlled
according to the condition of the vehicle, fuel economy and heating
performance may be improved.

[0130] Since two operating fluids exchange heat with the coolant through
one heat exchanger, structure and package may be simplified and
assembling processes may be reduced.

[0131] Since additional bifurcation circuits are not needed, production
cost may be curtailed, workability and utilization of space in a small
engine compartment may be improved, and a layout of connecting hoses may
be simplified.

[0132] If the operating fluid is the transmission oil in the automatic
transmission 40, hydraulic friction at a cold starting may be lowered due
to fast warm up. In addition, slip may be prevented and durability may be
maintained at driving due to excellent cooling performance. Therefore,
fuel economy and durability of the transmission may be improved.

[0133] Since the transmission oil and the engine oil are warmed up and
cooled down by using the coolant, heat exchange efficiency, cooling
performance, and heating performance may be improved compared with an
air-cooled type heat exchanger.

[0134] It is exemplified in this specification that the coolant, the
transmission oil, and the engine oil are used as the operating fluids,
but the operating fluids are not limited to these. All the operating
fluids that require warming up or cooling can be used.

[0135] In addition, the heat exchanger according to an exemplary
embodiment may further include covers and brackets that prevent damage of
the heat exchanger and other components or that are used for fixing the
heat exchanger to other components or the engine compartment.

[0136] For convenience in explanation and accurate definition in the
appended claims, the terms "upper", "lower", "inner" and "outer" are used
to describe features of the exemplary embodiments with reference to the
positions of such features as displayed in the figures.

[0137] The foregoing descriptions of specific exemplary embodiments of the
present invention have been presented for purposes of illustration and
description. They are not intended to be exhaustive or to limit the
invention to the precise forms disclosed, and obviously many
modifications and variations are possible in light of the above
teachings. The exemplary embodiments were chosen and described in order
to explain certain principles of the invention and their practical
application, to thereby enable others skilled in the art to make and
utilize various exemplary embodiments of the present invention, as well
as various alternatives and modifications thereof. It is intended that
the scope of the invention be defined by the Claims appended hereto and
their equivalents.